Move map generator into main repo (#2006)

## Description:

Move the MapGenerator repo into OpenFrontIO so we don't need to copy
generated map files over.

## Please complete the following:

- [x] I have added screenshots for all UI updates
- [x] I process any text displayed to the user through translateText()
and I've added it to the en.json file
- [x] I have added relevant tests to the test directory
- [x] I confirm I have thoroughly tested these changes and take full
responsibility for any bugs introduced

## Please put your Discord username so you can be contacted if a bug or
regression is found:

evan

resources/maps/pluto/manifest.json

@@ -1,12 +1,12 @@
 {
   "map": {
     "height": 1300,
-    "num_land_tiles": 1986092,
+    "num_land_tiles": 1987279,
     "width": 2100
   },
   "mini_map": {
     "height": 650,
-    "num_land_tiles": 489193,
+    "num_land_tiles": 489562,
     "width": 1050
   },
   "name": "Pluto",